"ET" wrote

I wonder about the cg issues with the rear mounted
fuel tank though (although obviously I trust Van to work that out...)

Van's spiel said that the cockpit is well forward of his other designs, with
the seat being in front of the main spar, instead of on top of it. With the
fuel tank just behind the seats, that would put it only slightly behind the
CG, so any weight changes during fuel burn would be small, due to such a
short moment arm of the tank's contents. That is what it sounds like to me,
anyway.
--
Jim in NC